Almost a decade ago, In 2010, Siri-Tarino and colleagues published a meta-analysis of prospective cohort studies evaluating the association between dietary saturated fat and cardiovascular disease in the American Journal of Clinical Nutrition. Based on the results of this meta-analysis, these researchers concluded that there was insufficient evidence from prospective cohort studies to conclude that dietary saturated fat increases the risk of coronary heart disease. However, a number of prominent diet-heart researchers identified many serious flaws and omissions in this meta-analysis that cast doubt on the validity of these researchers conclusions.
More recently, Chowdhury and colleagues published a separate meta-analysis in the Annals of Internal Medicine, and reached similar conclusions to that of Siri-Tarino and colleagues regarding the association between saturated fat and coronary heart disease. Unfortunately, this meta-analysis also failed to sufficiently address a number of important limitations that it shares with the meta-analysis by Siri-Tarino and colleagues. Furthermore, in this meta-analysis, although positively, but not significantly associated in the random-effects model, both dietary and total circulating concentrations of saturated fat were associated with a small, but statistically significant increased risk of coronary heart disease in the fixed effects model (RR=1.04 [95% CI, 1.01, 1.07] and RR=1.13 [95% CI, 1.03-1.25], respectively). These significant findings were however ignored in the conclusions of this study. Nevertheless, the media and proponents of popular Low-Carb and Paleo diets have repeatedly cited these meta-analyses as evidence to support a diet rich in saturated fat.
Saturated fat is not only a problem?
The findings reviewed by them support the hypothesis that saturated fat increases the risk of coronary heart disease mortality. Furthermore, as reviewed previously, evidence also suggests that the hazardous effects of diets rich in saturated fat are also applicable to diets rich in organic, grass-fed animal foods. However, saturated fat is only one of a number of problems as far as chronic diseases are concerned. The effect that a particular food has on the risk of coronary heart disease cannot be fully explained by saturated fat content alone, but rather by multiple nutrients that likely operate together in a complex manner to modify the risk of disease. Therefore, it may be more appropriate to focus attention on recommending healthy dietary patterns that are naturally low in saturated fat, while rich in dietary fiber and other beneficial nutrients; primarily, minimally processed, plant-based diets. Such a focus may be more effective to help lower the intake of saturated fat, while simultaneously improving overall dietary quality compared to the more contemporary reductionist approach of focusing on modifying single nutrients.
Only saturated fat intake cannot be responsible for heart disease – balance diet is required with lower saturated fat.